This invention relates to novel Friedel-Crafts Catalysts comprising molybdenum compounds. These catalysts are adapted for use in the Friedel-Crafts reactions for the aralkylation of aromatics to produce polybenzyls, the manufacture of aromatic ketones, aromatic sulfones and aromatic esters. These novel Friedel-Crafts Catalysts are molybdenum compounds, particularly molybdenum sulfide, molybdenum silicide, molybdenum selenide and molybdenum telluride.
It is an object of this invention to provide molybdenum containing compounds as catalysts for Friedel-Crafts reactions. It is a further object of this invention to provide molybdenum sulfide, molybdenum silicide, molybdenum selenide and molybdenum telluride as catalysts for the aralkylation of aromatics to produce polybenzyls, the manufacture of aromatic sulfones, aromatic ketones and aromatic esters. Further objects and advantages will become apparent as the description of my invention proceeds.
the aralkylation of aromatic hydrocarbons to produce polybenzyls and the manufacture of ketones, sulfones and esters using various Friedel-Crafts Catalysts has been known to the prior art. For some of these reactions Grosse and Ipatieff in J. Org. Chem. 1, 559 (1936) showed the following order of reactivity of Friedel-Crafts type catalysts: AlCl.sub.3 &gt;ZrCl.sub.4 &gt;TaCl.sub.5 &gt;BF.sub.3 &gt;CbCl.sub.5 &gt;TiCl.sub.4. R. E. Bunk in Twelfth Catalysis Report, John Wiley and Sons, New York, p. 266 (1940) has disclosed a generalized table of reactivity, as follows: AlBr.sub.3 &gt;AlCl.sub.3 &gt;FeCl.sub.3 &gt;ZrCl.sub.4 &gt;TaCl.sub.5 &gt;BF.sub.3 &gt;CCl.sub.4 &gt;TiCl.sub.3 &gt;WCl.sub.6 &gt;CbCl.sub.5 &gt;ZnCl.sub.2 &gt;SnCl.sub.4 &gt;TiCl.sub.4 &gt;BeCl.sub.2 &gt;SbCl.sub.5 &gt;HgCl.sub.2 &gt;CuCl.sub.2 &gt;BiCl.sub.3 &gt;AsF.sub.3.
The Friedel-Crafts Catalysts of the prior art have not been attractive in many instances due to the uncontrollable side reactions. The prior art Friedel-Crafts Catalysts also degrade under reaction conditions and during work-up, and are not recoverable. I have found that by employing molybdenum compounds such as molybdenum sulfide, molybdenum silicide, molybdenum selenide, molybdenum telluride, molybdenum boride and molybdenum carbide the disadvantages of the prior art Friedel-Crafts Catalysts are overcome.
I have discovered that the following molybdenum compounds MoS.sub.2, MoSi.sub.2, MoTe.sub.2, and MoSe.sub.2, MB and Mo.sub.2 C are useful as catalysts for Friedel-Crafts reactions. This discovery is surprising and totally unexpected in regard to the prior art teachings, as the molybdenum compounds have been considered inert chemically. In fact, MoS.sub.2 has been used widely as a lubricant because of its chemical unreactivity and related physical properties.
In comparison with the usual Friedel-Crafts Catalysts listed above the molybdenum compounds of my invention are not consumed in the reactor and may be recovered from the reaction medium unchanged, therefore avoiding expensive and troublesome workup. My catalysts are also inexpensive, stable at elevated temperatures, cause no pollution and are environmentally inert.
My catalysts are particularly suitable for use in the aralkylation of aromatics to produce polybenzyls, for the manufacture of aromatic ketones from aroyl halides and aromatics, for the manufacture of aromatic sulfones from aryl sulfonyl halides and aromatics and for the manufacture of aromatic esters from aroyl halides and phenol and for the benzylation of polystyrene.
The aralkylation of aromatic hydrocarbons is carried out by contacting aromatic halides in the presence of the novel molybdenum-containing catalysts at a temperature and pressure effective for promoting the aralkylation under the catalytic influence of the aforementioned molybdenum compounds. The aralkylation usually is conducted at a temperature of about 60.degree. to 250.degree. C. and the catalyst concentration is in the range of about 0.01 to about 15% by weight of reactants. The novel aralkylation process is suitable for the production of polybenzyls from benzyl halides and halogenated xylenes. In like manner, using applicant's novel catalyst ketones are produced from aroyl halides and aromatics and sulfones are produced from aryl sulfonyl halides and aromatics. Similarly esters are formed from aroyl hallides and phenols. In all these reactions, the reaction temperature is kept in the range of about 60.degree. to 250.degree. C. and if more than one reactant is present the mole ratio of the reactants is about 1:1 to 3:1. The molybdenum catalyst is usually employed at a concentration of about 0.01 to 15% by weight of the reactant. In some instances the reaction is conducted in the presence of inert hydrocarbon solvents such as benzene or xylene. The polybenzyls produced by the novel aralkylation process are useful as laminants and glass reinforced laminants. The ketones, particularly methylated benzophenones are useful as herbicides. The methylated diphenylsulfones and the related aroyl sulfones are used as stabilizers for polyesters.
The following examples illustrate the preferred embodiment of this invention. It will be understood that these examples are for illustrative purposes only and do not purport to be wholly definitive with respect to conditions or scope of the invention.